When high primary stability is achieved, immediate and early loading protocols have been reported safe and successful in the scientific literature.
In this section, you will find summaries on documentation of immediate and early loading using the Astra Tech Implant System'".
A retrospective analysis of peri-implant tissue responses at immediate load/provisionalized microthreaded implants
Immediate provisionalization of dental implants placed into fresh extraction sockets, carries with it many possible advantages not least significantly reduced manipulation of the tissues, reduced exchange of transmucosal components and an opportunity to preserve ridge dimension. It has been postulated that such advantages would be translated to a measurable maintenance of the crestal bone levels at the implant with a functionally and esthetically enhanced peri-implant mucosa. Such evidence has been presented for implants which benefit from a conical implant-abutment joint as well as microtex-turing and microthreading of the implant.
Purpose: This retrospective study was established to assess immediately provisionalized single-tooth implants to evaluate the peri-implant status up to 30 months following insertion.
Materials and Methods: Twenty-eight subjects treatment planned for the extraction of one or more teeth were enrolled to the study. Patients were not required to be dentally fit, and local infection or smoking were not considered as exclusion criteria.
Implants were placed at the time of extraction and implant dimensions were matched to the size of the extraction socket and the available bone apical to the socket. Either Direct Abutments or Bi-Abutments were secured to the implants using manual finger torque and provisional crowns were fabricated from resin and cemented with permanent cement. All implant related or abutment related complications were noted and marginal bone levels were assessed relative to a fixed reference point on the implant at x7 magnification.
In 20 patients a clinical examination at 6 and 30 months, allowed assessment of the peri-implant soft tissues in order to measure pocket depth (PPD) at 6 points around each implant and to record bleeding on probing (BOP). Papilla fill was also assessed mesially and distally and scored using the Jemt index.
Results: A total of 43 implants were placed as far distally as the premolars. In 3 patients 4 implants became mobile within 6 weeks and were removed and replaced. These patients were excluded from the study leaving 25 patients with 39 implants (12 central incisors, 9 lateral incisors, 5 canines, and 13 premolars).
Mean PPD measured 3.0 mm interproximally and 2.5 mm in the midfacial zone and in general there was an absence of BOP. Marginal bone data revealed a mean bone loss of 0.32 mm mesially and 0.27 mm distally. Only 3 implants were associated with bone loss greater than 1.0 mm with approximately 85% demonstrating bone loss of less than or equal to 0.50 mm. The mean distance from the peak of bone to the contact point measured 4.53 mm mesially and 4.05 mm distally. This limited bone loss was reflected in 95% of all papillae scoring 1 or 2.
Discussion and Conclusion: The current study supports previously published data for this particular implant design to confirm that a propitious marginal bone level can be maintained over the long-term. This bone maintenance may be related to a number of factors besides implant design, in particular the use of minimal surgical trauma with an absence of periosteal stripping, the use of a definitive abutment at the time of implant placement thereby avoiding swopping out of abutments, which can disrupt the delicate junctional epithelium, as well as the use of pure titanium or ceramic abutments which have been shown to offer an enhanced soft tissue response. Furthermore depth of implant placement has been shown to affect marginal tissue response with concerns for deep margins leading to tissue irritation exacerbated by deep excess cement which cannot easily be removed.
In the current study the PPD measurements as well as the distances measured from bone to the contact points support the proposals of others that a biologic width exists around implants, which requires a dimension of around 2.5 mm to be established and that in the presence of this dimension a full papilla can exist alongside bone which remains level with the implant-abutment interface. When the various considerations described above are respected it appears possible to obtain a predictable peri-implant health with implants immediately placed and provisionalized after tooth extraction.
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